1. Technical Field
This invention relates in general to systems for color matching and, more specifically, to systems for analyzing and matching tooth shades. Such systems are of particular use in manufacturing dental prosthetics (e.g., crowns, bridges, veneers, and prosthetic teeth) to repair, replace or alter natural teeth, in various dental tooth whitening procedures and to enable communication between patient, dentist and lab technician concerning such procedures.
2. State of the Art
Dentists often repair or replace a diseased, damaged, or unsightly natural tooth of a patient with a crown, bridge, veneer, or prosthetic tooth. One obvious goal in performing such a repair or replacement is to provide the patient with a natural-looking smile despite the presence of the prosthesis. Attempts to reach this goal generally involve matching the color of the prosthesis to the color of the natural tooth being repaired or replaced, and to the colors of the natural teeth that are adjacent where the prosthesis will be placed.
Similarly, dentists often perform various tooth whitening procedures on a patient's natural teeth to reverse the effects of aging, coffee drinking, smoking, and similar activities on the patient's dental appearance. The goal in such procedures is also to provide the patient with a natural-looking smile, and attempts to reach this goal also generally involve color matching.
To this end, manufacturers of the various colored porcelains, resins, compomers ceramers or other direct restorative materials conventionally used in making dental prosthetics, or in repairing discolored, chipped, broken or malformed teeth, typically provide color matching shade guides to dentists which illustrate the various colored porcelains available. As shown in FIG. 1, one such shade guide 10 includes a variety of shade tabs 12, each made of a different colored porcelain available from a manufacturer. A dentist determines the color of a patient's natural teeth by detaching individual shade tabs 12 from the shade guide 10 and holding the shade tabs 12 next to the patient's natural teeth for comparison. Once a color match is found, the dentist orders a dental prosthesis from a dental laboratory in the matching colored porcelain or other material, or, if the patient's teeth are being whitened, the dentist uses the color match as a base against which to compare the eventual results of the whitening process.
This somewhat rudimentary method often provides less than desirable results because of the inaccuracy inherent in the dentist "eyeballing" the color match. Poor lighting, poor vision, eye fatigue, conflicting ambient colors or even lack of patient cooperation in the process, among other things, can cause the dentist to miss the best match. More importantly, the best match is often a combination of two or more colored porcelains, sometimes from different manufacturers, which is difficult to discern by the human eye.
Accordingly, a variety of mechanical and electronic devices have been devised to aid in matching tooth shades. Some of these devices are described in U.S. Pat. Nos. 5,766,006 to Murljacic, 5,759,030 to Jung et al., 5,690,486 to Zigelbaum, 5,529,492 to Yarovesky et al., 5,383,020 to Vieillefosse, 5,055,040 to Clar, 4,654,794 to O'Brien, and 4,110,826 to Mollgaard. Unfortunately, none of these devices has been very successful in advancing the tooth shade matching process much beyond the "eyeballing" procedure described above.
Therefore, there is a need in the art for an improved tooth shade matching system.